Process for producing high polymers of alpha-olefins and catalyst compositions therefor



Aug. 27, 1968 KEIICHI AZUMA ETAL 3,399,184

PROCESS FOR PRODUCING HIGH POLYMERS OF ALPHA-OLEFINS Filed April 9, 1965POLYMERIZATION SPEED IOO AND CATALYST COMPOSITIONS THEREFOR 2Sheets-Sheet 1 EFFECT BY THE ADDITION OF DICYCLOPENTADIENYL TITANIUMPOLYMERIZATION TIME (Min) EFFECT BY THE ADDITION OF DIALKYL ZINC 025 I002.00 O 0 3 0 6 0 9 0 I2 O I50 Aug. 27, 1968 Filed April 9, 1965 N.(NLQIQNCD 0 000000 -KElICH| AZUMA ETAL 3,399,184 PROCESS FOR PRODUCINGHIGH POLYMERS OF ALPHA-OLEFINS AND CATALYST COMPOSITIONS THEREFOR 2Sheets-Sheet 2 EFFECT OF THE MELT INDEX OF THE POLYMER BY THECONCENTRATION OF Zn(C H I I I I l I I I United States Patent" 3,399,184PROCESS FOR PRODUCING HIGH POLYMERS OF ALPHA OLEFINS AND CATALYSTCOMPOSI- TIONS THEREFOR Keiichi Azuma, Kazuo Shikata, and KaijiYokolrawa, Tokuyama-shi, Japan, assignors to Tokuyama Soda KabushikiKaisha, Tokuyama -shi, Yamaguchi ken, Japan, a corporation of JapanFiled Apr. 9, 1965, Ser. No. 446,839 Claims priority, application Japan,Apr. 13, 1964, 39/20,583; May 21, 1964, 39/28,329

6 Claims. (Cl. 260-935) ABSTRACT OF THE DISCLOSURE A novel catalyst forproducing alpha-olefin high polymers which is obtained by reacting a lowvalent titanium halide, .a polyalkylhydrosiloxane, dicyclo pentadienyltitanium, and if desirable a dialkyl zinc, and a process for producingsaid alpha-olefin high polymers using the above catalyst.

This invention relates to a process for obtaining linear polymers ofhigh molecular weight by polymerizing or copolymerizing thehereinafter-defined alpha-olefins, using a new catalyst. The inventionalso relates to the new catalyst composition for polymerizing orcopolymerizing alpha-olefins.

As processes for obtaining highlycrystallinepolymers by polymerizing thealpha-olefins such as ethylene and propylene, known are the processeswhich use the Ziegler- Natta type catalystwhich comprises the reactionproduct of the halides of titanium of low valence and principally theorganic aluminum compounds.

According to the present invention, it has been found however that acatalyst composition comprising either the three components of a lowvalent titanium halide, a polyalkylhydrosiloxane and dicyclopentadienyltitanium or the four components consisting of the foregoing threecomponents to which has been added further a dialkyl zinc was a catalystpossessing very high polymerization activity with respect toalpha-olefins.

As regards the catalysts comprising only the compounds of Group IV ofthe Periodic Table, the catalysts comprising the reaction products ofhalides of Group N51 with organic silicon compounds containing a H-Sibond are already known.

Further, as a catalyst using only the compounds of the metals of GroupWar, the catalyst of the composition consisting of TiCl and (C H -Ti(CHas disclosed in US. Patent 2,992,212, is known.

Although this catalyst has relatively good polymerization activity withrespect to propylene, it possesses such drawbacks as that not only thesynthesis of is di-tficult but also its instability with respect totemperature and its difficulty of handling. There is also the problem asto whether its commercial production is feasible. Hence, it is believedto possess little value as a commercial catalyst.

Besides the foregoing catalysts, there is one proposed as an improvementof the Ziegler-Natta type catalyst. This is a three-component catalystcomprising the reaction product of an organic silicon compoundcontaining a I-I-Si bond, a halide of a metal of Group III of thePeriodic Table (particularly aluminum trichloride) and a compound of ametal of Group N1: of the Periodic Table.

The catalyst composition according to the present invention has howevera higher catalytic activity than the prior art catalysts such asdescribed hereinbefore, and

3,399,184 Patented Aug. 27, 1968 moreover polymers of alpha-olefinshaving higher isotacticity can be obtained by the catalyst of thepresent invention.

The low valent titanium halides and polyalkylhydrosiloxanes, thecomponents making up the catalyst according to this invention, arereagents that are readily obtainable commercially. On the other hand,dicyclopentadienyl titanium can be readily synthesized by reducingdicylopentadienyl titanium dichloride in a hydrocarbon solvent using asodium amalgam. The catalyst COIIIPOSI'. tion consisting of the reactionproduct of these three components has an activity whose duration isgreat as well as a fast polymerization speed. Further, the catalystcomponents used in this invention, except the metal halides, are allsoluble in hydrocarbon solvents. Again, the fact that the procedure forsynthesizing the catalyst is simple as well as that the equipment willsuflice with the common agitating type satisfies the requisites of acommercial catalysts.

The following is an illustration of a process for producing theinvention catalyst. First, the interior of an electromagneticstirrer-equipped autoclave is replaced with an inert gas, after whichthe autoclave is charged with a solvent. Then, under an atmosphere of aninert gas, titanium trichloride, a polyalkylhydrosiloxane, anddicyclopentadienyl titanium are added in mole ratios of TiCl (C H Ti,2.0-0.2 and polyalkylhydrosiloxane/ (C H Ti, 1-10. The polymerizationspeed changes with the changes in these two mole ratios. In adding thecatalyst components, the dicyclopentadienyl titanium and thepolyalkylhydrosiloxane may be treated in advance for 10-30 minutes atroom temperature (ZS-30 C.) and then the titanium trichloride be added,or the three components may be together at the same time.

The present invention also includes a process for producing afour-components catalyst comprising the foregoing three components towhich has also been added a small amount of a dialkyl zinc, as well as aprocess of producing polymers of alpha-olefins, using said catalyst. Thefour-components catalyst in accordance with the invention wil providehighly polymerized and highly crystalline polymers when monomers arepolymerized and rubbery or block polymerized high polymers when amonomeric mixture is used. In the case of the invention catalystcomposition wherein a dialkyl zinc has been incorporated, polymers ofstill higher crystallinity can be obtained in good yield per unitcatalyst at high polymerization speeds. Preferred is the use of thedialkyl zinc in an amount such that Zn/Ti mole ratio becomes not morethan 3, marked effects being had even with the use in such minuteamounts as below 1.

Next, the properties of the invention catalyst composition will becompared with those of the conventional catalysts, taking, for example,the polymerization of propylene. In accordance with the polymerizationprocess using as catalyst that comprising a titanium trichloridethermally reduced with hydrogen and triethylaluminum the averagepolymerization speed is 40 g./TiCl g./hour and the resulting polymerexhibits an isotactic content (which is indicated by the percent boilingn-heptane extraction residue) of -86%. On the other hand, in the casealso of a catalyst wherein as the organic aluminum compound was useddiethylaluminum monochloride, the polymerization speed was 10 g./TiClg./h0ur and the isotactic content was about 93%.

In contrast, when TiCl was used in the invention threecomponentscatalyst, the polymerization speed was 40-50 g./TiCl g./ hour and theisotactic content was about Further, by the incorporation of the dialkylzinc, the polymerization speed could be raised to 80-100 g./TiCl g./hourand the isotactic content to the neighborhood of 95 Thus, as hereinabovedescribed, not only is the p lymerization speed high when the inventioncatalyst is used, but also polymers of alpha-olefins having highisotactic contents can be obtained;

Although the invention catalyst shows a tendency to a somewhat rapiddecline in its catalytic activity with the passage of time inpolymerizing ethylene, as compared with the instances of thepolymerization of alpha-olefins having 3 or more carbon atoms, it is, ofcourse, possible to use the invention catalyst in homopolymerizingethylene or copolymerizing ethylene with the alpha olefins having 3 ormore carbon atoms.

The behavior of the activity of the invention catalyst is as illustratedin FIG. 1. As the mole ratio of dicyclopentadienyl titanium (hereinafterabbreviated to TC) to titanium trichloride increases, the polymerizationspeed rises. Namely, in FIG. 1 are shown the changes in thepolymerization speed with the passage of the polymerization time inpolymerizing propylene, using as catalyst compositions consisting of 2millimoles of TiC1 6.7 millimoles Si-H compound and 1.0 millimole of ZnRbut in which the TC alone was varied so as to be respectively 0, 0.5,0.7 and 1.3 mole times the TiCl On the other hand, that indicated asNatta in the figure is a control which uses as catalyst TiCl -AlEt Cl.That marked is the instance where hydrogen reduced TiCl (HA-StaufferCompany product) was used, whereas that marked is the instance wherealuminum reduced TiCl (AA-Stauifer Company product) was used.

It can be seen from the results shown in FIG. 1 that it is preferred touse the titanium trichloride according to the invention in an amount atleast 0.5 mole times, and particularly at least 0.7 mole times, thedicyclopentadienyl titanium (TC). As regards the upper limit of theamount to be used of TC, a sufficiently high polymerization speed can beobtained usually by the use of TC in an amount such that TiCl /TC is onthe order of 0.2, i.e., about 5 mole times the TiCl While the amountused of the TC can exceed this amount without any harm, the use thereofin greater amounts will be economically 'a disadvantage.

On the other hand, as regards the amount used of thepolyalkylhydrosiloxane, nearly the maximum polymerization speed isattained by using polyalkylhydrosiloxane in a molar ratio of 1:1, basedon the titanium trichloride. The use of a greater amount than that tendsto enhance the duration of the catalytic activity rather than increasethe polymerization speed.

The dialkyl zinc, as used in this invention, has, on the other hand, theeifect of enhancingthe polymerization activity of the catalyst as wellas the effect of controlling the molecular weight of the resultingalpha-olefin polymer. When considered from the aspect of polymerizationactivity, the use of the dialkyl zinc in an amount of less than 3 moles,based on the titanium trichloride, will do, the end being fully attainedby 0.1-0.5 mole. The effect of dialkyl zinc is shown in FIG. 2. It canbe seen from FIG. 2 that in the case where 2 millimoles of TiCl 0.7millimole of TC and 1.4 millimoles of a polyalkylhydrosiloxane have beenused, a satisfactory polymerization speed can be obtained by the use ofthe ZnR in an amount on the order of 0.2-2.0 millimoles, i.e., whenZn/Ti is about 0.1-1. It is, of course, possible to use a greater amountthan this, there being observed :a tendency to the molecular weight ofthe resulting polymer being controlled (decline thereof) when the ZnR isused in a relatively large amount. However, since there will be somechanges in the amounts used of the foregoing components in the inventiondepending upon the composition of the catalyst starting materials, theconditions of catalyst preparationv and polymerization conditions, theamount used of the several components are not necessarily limited to themole ratios hereinbefore specified.

When it is contemplated to lower the molecular weight of thealpha-olefin polymer, the concentration of the dialkyl zinc in thesolvent is particularly influential. As an illustration thereof, in FIG.3 -is shown by means of the melt index the relationship between theamount incorporated of the dialkyl zinc and the molecular weight of theresulting polymer.

It .can be seen from this figure that the molecular weight of theresulting polymer declines as the concentration of the dialkyl zinc inthe solvent rises.

When the catalyst is prepared by commonly practiced procedures, somedifferences in'polymerization activity are observed on occasionsin thecatalystsystem according to this invention wherein is used a dialkylzinc, depending upon even the sequence in which the components areadded. A convenient sequence of addition of the several componentsis-that,' for example, in the following method, wherein the dialkyl zincand polyailkylhydrosiloxane are reacted for 10 minutes at 2030 C. underan atmosphere of either an inert gas or the olefin gas used, after whichthe dicyclopentadienyl titanium is introduced and reacted for 10 minutesunder identical conditions and thereafter the titanium trichloride isadded.

Although the activity mechanism of the catalyst system of the presentinvention is not clear, it must basically be a three-component catalystand for obtaining its catalytic activity the use of a low valenttitanium halide, dicyclopentadienyl titanium and a compound wherein ispresent a Si-H bond, such as a polyalkylhydrosiloxane, is necessary. Forinstance, even though a polyalkylhydrosiloxane not having a'Si H bond isused under the preferred conditions of the invention process, an activecatalyst cannot be obtained.

There are no special restrictions as to the procedures for carrying outthe polymerization reaction using the invention catalyst system, itbeing possible to use, without any change, the procedures followed inthe low-pressure polymerization of olefins, as customarily practiced.For example, as the polymerization temperature is used a temperatureranging from room temperature to C., and preferably 5080 C. There are noparticular restrictions as to the pressure, but usually a pressure of210 ltg/cm. is used.

The term alpha-olefins, as used herein, include, e.g., ethylene,propylene, butene, styrene and butadiene. Any of these alpha-olefins canbe homopolymerized or copolymerized. Copolymers are produced by addingthe monomers concurrently, while by employing the known technique ofintroducing the several olefins alternately either random or block.polymers are obtained.

As the three components of the catalyst system according to thisinvention, those which come respectively within the following scopes areused. Namely, as the low valent titanium halide, at least one memberselected from the group consisting of titanium dichloride, titaniumtrichloride, titanium dibromide, titanium tribromide, titanium diiodideand titanium triiodide is used, the most effective being titaniumtrichloride. As methods of preparing titanium trichloride, known are themethod of reducing titanium tetrachloride with hydrogen and the methodof reducing titanium tetrachloride with metallic aluminum. In the lattercase, it is said that a cocrystallized composition of TiCl and AlCl isformed. These are all referred to herein generically as titaniumtrichloride.

Next, the polyalkylhydrosiloxane is a silicon compound which comprises asilicon atom to which are directly bonded hydrogen and alkyl. Of the.alkyl radical, that of methyl is readily available, but that of ethyland propyl are also effective. Further, the polyalkylhydrosiloxane to beused in the invention may also be one in which a part of the alkylradical is substituted with phenyl or a substituent phenyl. In short, solong as the polyalkylhydrosiloxane to be used-in this invention is onein which the alkyl and hydrogen are bonded to at least a part of thesilicon atom (Si) of the SiO-- chain and one, which is soluble in thehydrocarbon solvent to be used during the polymerization reaction, itwill do.

Next, the dicyclopentadienyl titanium compound is a compound comprisinga divalent titanium to which have been bonded two cyclopentadiene rings.

On the other hand, the dialkyl zinc is one in which the alkyl radical ismost preferably methyl or ethyl, there being a tendency to a decrease inits effectiveness as the number of carbon atoms increases. Hence, thosesuitable commercially are the ones having an alkyl of 14 car bon atoms,dimethyl and diethyl zinc being especially useful.

6 Control 3 The same procedures as described in Example 1 were followedexcept that instead of the (C H Ti 1 mmol of (C H TiCl was used. A solidpolymer could not be obtained.

EXAMPLE 3 An electromagnetic stirrer-equipped 500-ml. stainless steelautoclave provided with a pressure gauge, a thermometer, a propyleneinlet line and a feeding mouth was For a clearer understanding of theinvention, the folcharged under an atmosphere of an inert gas with 150ml. lowing examples are given, it being understood that these 0fn-heptane, 0.4 ml. of polymethylhydrosiloxane, 12.5 examples are onlyfor purpose of illustration and not in mi. of a solution of (C H Ti (lg./50 cc. in toluene), limitation of the present invention. in the ordergiven. After carrying out the reaction for about minutes at -30" C. in apropylene atmos- EXAMPLE 1 phere, 0.3 g. of TiCl (HA-Staulfer Companyproduct) Ah electromagnetic stiffer-equipped Stainless was added,following the polymerization reaction was steel autoclave thoroughlyreplaced with ethylene in adarried out by raising the temperature to68-70 C. with Vance was charged With 150 of p gof stirring and with aconstant propylene pressure of 5 poiymethyihydfosiioXahe f toluene), 1mmol 20 kg./cm. The polymerization reaction was completed of 5 5)2 oftoluene) and mmois with a polymerization time of 4 hours. After cooling,Ticis (HA'Stautief Company P in the order given, the resulting polymerwas introduced into 200 cc. of while fl g a small amount of ethyleneWhen this methanol, after which it was filtered and again washed wasthen heated immediately, the polymerization started i 200 f methanol andan id l i f h d in about 5 mil'lutes- The Polymerization temperature Was25 chl-oric acid. The resulting polymer became a white powmaintained atWhen the ethylene Pressur e der, which was collected by filtration.After washing with Came 2 g Was again Supplied P to 6 -a water anddrying, 59 g. of the polymer was obtained. this Procedure 'hemgthereafter repeated The P l The n-heptane extraction residue of thisproduct was zation reaction was carried out for 2.5 hours. Th 94%polymer was treated with methanol, filtered and dried to Oh the otherhand, when the same experiment was Yield of a White Solid p ymer.repeated except that 0.6 g. of TiBr was used instead of EXAMPLE 2 TiClthe yield was /3 of that obtained in the foregoing experiment.

After stirring 0.24 g. of polymethylhydrosiloxane (in EXAMPLE 4 75 ml.of toluene) and 1 mmol of (C H Ti (in 12.5 ml. of toluene) along with130 ml. of n-heptane for 20 min- The Same Procedures as described 111Example 3 were utes at room temperature under at atmosphere ofethylfollowed- The Polymerization of P py Was cai'fiod ene, 0.32 g. ofTiCl (HA) was added. When heating was out using as materials making pthe catalyst sof started with the ethylene pressure at 4 kg./cm. theTiCls (Stautiter P Y- of P y polymerization reaction started immediatelyand a drop in hydl'osiioxehe and 25 of Solution of 5 5)2 the ethylenepressure was noted. Thereafter the same pro- 40 gill toh1ehe)- 43 ofSolid P y were cedures as described in Example 1 was followed. After ateihed With a Polymerization time of hours- The polymerization time of2.3 hours, 54.0 g. of solid polymer hePtane eXtfeotiol'1 residue of thisP t was 90.2%. were b i d When 0.6 g. of TiCl was used instead of theTiCl On the other hand, when, instead of the TiCl obtained the n-hePextraction residue was by reducing titanium tetrachloride with hydrogen(here- 45 Control 4 inafter to be indicated as HA), 0.25 g. of TiCl wasused but otherwise the same procedures were followed, the Exomple 4 wasrepeated P P that 5 5)2 z was polymer yield wa about /3 of that of theinstance hereused msteati of the s sh t a Solid Polymer could inbeforedescribed. not be Obtamfd- Control 1 EXAMPLE 5 Instead of the TiCl (HA)used in Example 1, 0.50 The results obtained when the polymerizationreaction g. of TiCl (31.6 wt. percent thereof dissolved in toluene) wascarried out in accordance with the invention process was used. Otherwisethe same procedures, as described in similar to that described inExample 3 and by using the Example 1, were followed. The polymerizationreactions same polymerization equipment and solvent andunder werecarried out for 2 hours respectively at 80 and 130 identical conditionsexcept that a catalyst of the so-called C., but a solid product couldnot be obtained. Ziegler-Natta type was used are shown in Table I,below.

- TABLE I Polymerization Conditions Polymer Properties CatalystComponents Temp., Time, Propylene n-Heptane Yield Shrinkage, nHeptane C.hr. Pressure, Amount, MI* Strength, Percent (1 Residue,

kgJcm. cc. kg./cm. Percent An example of the TiCMHA), 0.32 g

invention catalyst. {Si compound, 0.4g U} 67i2.5 4.0 5.0 200 0.01 248 487.0 93.4

(G5H5)2Tl, 0.13 g Ziegler-Natta type TiCMAA), 0.38 g

catalyst. {AlOlEtz 67:1:25 4.0 4.0 200 0.01 239 44 7. 73 94.7

Al/Ti mole ratlo==2 *MI=Melt index.

EXAMPLE 6 Control 2 The same procedures as described in Example 1 werefollowed except that instead of the (C H T i 1 mmol of (C H TiCl wasused. A solid polymer could not be obtained.

TABLE II.RESULTS OBTAINED WHEN ETHYLENE WAS POLYMERIZED Catalystcomponents, mol Polymerization conditions Polymerization results, g.

TiCln Silicon compound Additive Solvent, 1111. Pressure, Tcmpera- Time,I Oily Solid atni. ture, C. lir. Product polynicr Invention 'IiCh,0.0043 Polyniethylhydro- (C 115) {FL 0.002 n-Heptanc, 150.," 25 70-80 2.5 78 catalyst. Siloirarie, 0.0067.

TiCl 00021.-.- Polymotl'iylliydro- (C H5):Ti, 0.002 n-Hoptano, 150..-2-5 7080 2. 3 0 55.

siloxane, 0.0033. 'IiCl 0.0043 (C H )2Ti 0.002 do. -80 2.0 0 l5 TiCl00043..-. Polymetliylliydrod 25 7080 2.0 0 0 siloxane, 0.0067. Control5..-" TiCh, 0.06 Dimetliyl-phcnyl- 60-80 C. Irac- 50 6 2. 6 7.0

silano, 0.12. tiou refined oil, 200. TiCl 0.00 do do 50 100 6 0 '170Control 6 TiCli, 0.01 Polymethylliydro- AlCh, 0.023- 200 Atin. S5 3 0 08siloxane, 0.166.

TABLE III.RESULTS OBTAINED WHEN ETHYLENE WAS POLYME RIZED Catalystcomponents, mol Polymerization conditions Polymerization results, g.

TiCl Silicon compound Additive Solvent, ml. Pressure, Teinpera- Time,Oily Solid atm. turc, percent hr. Product polymer Invention T1013,0.0043... Polymcthylliydro- (C Hmli, 0.002--. n-Hcptane, 158... 5 68-702.0 0 43 catalyst. siloxane, 0.0067.

T1013, 0.0023 Polymethylhydro- (C5115) 2T1, 0.001 .do 5 68-70 4. 0 0 02.4

siloxane, 0.00134. Control 7 TiCh, 0.06 Dimethylphenyl 200 100 (i 18.82.2

silaiie, 0.12. TiCl 0.08 Trimetliylsilane, 200 100 6 0 0 Control 8-T1013, 0.0005- Polynietliylliydro- AlCla, 0.0075 7080 0. fraction 120 0siloxane, 0.14. ligroin, 150. TiCl, 0.0042 .do A1013, 0.0075 do 115-1200 Control 9 TiCl 0.0043 (CsHshTi, 0.002.-- n-Heptaiie, 150..- 5 68-703.0 0

l Propylene, 350g. 2 Unknown. 3 Viscous, sticky, rubbery substance.Yield unknown. 4 Small amount.

EXAMPLES 7-1 1 An electromagnetic stirrer-equipped SOO-ml. stainlesssteel autoclave was charged with 200 m1. of n-heptane, after which 0.12g. of ZnEt 0.4 g. of polymethylhydrothen the rest of the components wereadded to this reaction mixture and reacted for about 10 minutes at 20-30 C. The results are shown in Table IV, wherein DC, TC and ZnEt denotepolymethylhydrosiloxane, dicyclosiloxane (Dow product DC-l107;hereinafter abbreviated 4o pentadienyl titanium and diethyl zinc,respectively.

TABLE IV n'Heptano Yield Example Addition Sequence Polymer, Polymer, g./Extraction Strength, 1

g. TiCli, g./Time Residue, kg./cm.;

V percent 7 (DC-TC-TiOl3)-ZI1EL2 46. 0 57. 5 95. 2 267. 4. 2 8.-.(DC-ZnEtzi'IC-TiCb 49. 9 62. 4 95. 5 285 4. 6 9 (DC-ZIlEtz-TC)-T1Cl3 32.5 40. 6 94. 9 255 4. 2 (D CTC)-TiC1rZ11Etz 35. 4 44. 3 95. 3 3. 8

.- (D CTC)-T1Cl; 10. 5 16. 4 92. 5 5. 5

*1; denotes the intrinsic viscosity measured in tetrolin at 135 C.

to DC), 0.13 g. of (C H Ti and 0.32 g. of TiCl (HA) were introducedunder an atmosphere of either an inert gas or the olefin gas used. Thereaction was then carried out for 2.5 hours at a polymerizationtemperature of 70 C. with a constant propylene pressure of 5 kg./cm.After washing the resulting polymer with methanol, it was washed furtherwith methanol and hydrochloric acid, followed by filtration and dryingto yield a White powdery polymer.

This example shows a comparison of the catalytic activity and thesequence of addition of the various components. First the componentsincluded in the parentheses below were reacted for about 10 minutes at2030 C.,

EXA PLE 12-16 TABLE V n-Heptane Yield Example ZnE t2, ZnEt2/T Cl3,Polymer, Polymer g./ Extraction Strength, 1;

g. mol ratio g. TiCl; gJhour Residue, kgJcmz percent The instance when0.085 g. of DO was used.

9 EXAMPLE 17-20 The procedures as described in Example 7 were followedto polymerize ethylene, except that the reaction was carried out at 70C. using 250 ml. of the solvent and an ethylene pressure of 26 kg./cm.The method of treating the polymer was the same as in the case whenpropylene was polymerized. The results obtained are shown in Table VI,below.

TABLE VI Polymeri- Stress at Example TiCls, TO, DC, ZnEt ration Polymer,Specific Breaking g. g. g. g. Time, g. Gravity point,

hr. kg/cm.

When dimethyl zinc was used instead of diethyl zinc in this experiment,the results obtained were exactly the same. On the other hand, whensimilar procedures were employed but using dibutyl zinc, the effectswere about one half of that obtained with the use of either diethyl ordimethyl zinc.

EXAMPLES 21-25 The copolymerization of ethylene and propylene wascarried out under identical conditions as in Example 1, except thepolymerization reaction was conducted by the introduction of the gas ofprescribed composition at an initial pressure of 4-5 kg./cm. but with nofurther replenishment thereof. In the case of the three-componentcatalyst, the catalyst was prepared using the sequence of addition ofthe components of (DC-TC)TiCl While in the case where ZnEt was added,the sequence was (DC-ZnEt )TC-TiCl Thus, the procedure used was one inwhich no consideration was given to the changes of the gas compositionwith the passage of time. The reaction was carried out at a temperatureof 70 C. using 0.32 g. of TiCl (HA), 0.25 gfof TC and 0.4 g. of DC. Thepolymer was practically soluble in the solvent. This was diluted withmethanol and the separating polymer was collected by filtration. Theresults obtained are shown in Table VII, below.

2. A process for producing high polymers of alphaolefins, whichcomprises efifecting the polymerization reaction of at least onealpha-olefin in the presence of a catalyst obtained by reacting titaniumtrichloride, a polyalkylhydrosiloxane, dicyclopenadienyl titanium and adialkyl zinc or" 1 to 4 carbon atoms, in such proportions that thetitanium trichloride/dicyclopentadienyl titanium mole ratio rangesbetween about 2.0 and 0.2, the polyalkylhydrosiloxane/dicyclopenadienyltitanium mole ratio ranges between about 1 and 10, and the zinc metal/titanium metal mole ratio ranges between about 0.1 and 1.

3. The process according to claim 1 wherein said polymerization reactionis carried out in the presence of a hydrocarbon solvent.

4. The process according to claim 2 wherein :said polymerizationreaction is carried out in the presence of a hydrocarbon solvent.

5. A catalyst composition for use in polymerizing alphaolefinscomprising a mixture of titanium trichloride, a polyalkylhydrosiloxaneand dicyclopentadienyl titanium in such proportions that the titaniumtrichloride/dicyclopentadienyl titanium mole ratio ranges between about2.0 and 0.2 and the polyalkylhydrosiloxane/dicyclopentadienyl titaniummole ratio ranges between 1 and 10.

6. A catalyst composition for use in polymerizing al- TABLE VII EthyleneInitial Ethylene Content n-Heptane Example ZnEtz, Content of Pressure,Reaction of Gas at Comple- Polymer, Form Extraction g. Gas Fed, kg./em.Time tion of Reaction, g. Residue,

percent percent Percent 29. 5 4. 0 hr 4. 4 Rubbery 10 29. 5 5. 1 3. 414. 0 Bristly 36. 2 19.4 5.6 1.1 15.7 do 34.0 19.4 4.3 2.1 8.5 ...do20.0 68. 8 4. 8 10 min 4. 3 Rubbery 9 EXAMPLE 26 pha-olefins comprisinga mixture of titanium trichloride,

The same procedures as described in Example 7 were followed, the methodof synthesizing the catalyst being one in which 0.4 g. of DC and 0.12 g.of ZnEt were first reacted, then 0.32 g. (1.3 mmol) of (C H Ti and TiClbeing added. The molar ratio of TC/TiCl was 0.65. The so obtainedcatalyst was used to polymerize propylene. With a polymerization time of2.5 hours, 85.5 g. of polypropylene were obtained. The polymerizationtime in this case becomes 112 g. polymer/ g. catalyst/time. Theresulting polypropylene had the following physical properties: aspecific gravity of 0.9128, a melt index of 0.02, a yield strength of262 kg./cm. an n-heptane extraction residue of 93.3% and a shrinkage of42%.

When titanium triiodide and tribromide were used instead of titaniumtrichloride, the yield declined and became about one half of thatobtained by the use of the latter.

We claim:

1. A process for producing high polymers of alphaapolyalkylhydrosiloxane, dicyclopentadienyl titanium and a dialkyl zincof 1 to 4 carbon atoms, in such proportions that the titaniumtrichloride/dicyclopentadienyl titanium mole ratio ranges between about2.0 and 0.2, the polyalkylhydrosiloxane/dicyclopentadienyl titanium moleratio ranges between about 1 and 10, and the zinc metal/titanium metalmole ratio ranges between about 0.1 and 1.

JOSEPH L. SCHOFER, Primary Examiner.

M. B. KURTZMAN, Assistant Examiner.

